Motor and brake mechanism



1949. ca. D. WlLLlTS MOTOR AND BRAKE MECHANISM 2 Sheets-Sheet 1 Filed March 5, 1948 Invent-or. Glenn llwillits, Hi gorhey.

Feb. 15, 1949. e. D. WILLITS 2,462,017 MOTOR AND BRAKE MECHANISM Filed March 5, 1948 2 Sheets-Sheet 2 Fzg- ,f

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Glenn D.Willits, s9 z4 ,1, by M 7 His Att c r" hey.

Patented Feb. 15,1949 2,462,017 I.

UNITED STATES PATENT OFFICE 2,462,017 MOTOR AND BRAKE MECHANISM Glenn D. Willits, Leo, Ind., assignor to General Electric Company, a corporation of New York Application March 5, 1948, Serial No. 13,124 12 Claims. (Cl. 172-36) This invention relates to motor and brake Fig. shows the exterior arrangement of the mechanisms and more particularly to such a terminals; Fig. 6 is an elevational view, partly mechanism having its major components perin section, of a portion of the mold for molding manently bound together by molded insulating the mechanism of Fig. 1 showing the components material to formaunitary structure. 5 to be molded positioned therein; Fig. 7 is a In. the design of dynamoelectric machines, vertical cross section of the mold of Fig. 6 taken particularly for use on aircraft, it is frequently along the line 77; and Fig. 8 is a schematic necessary to provide a structure capable ofwithcircuit diagram of the mechanism. standing prolonged severe vibration. Brake Referring now to Fig. 1, there is shown the mechanisms are frequently associated with such ll improved motor and brake mechanism of this dynamoelectric machines, for example, in a pitch invention in which the motor portion is desigchanger for aircraft propellers, and it is denated generally as l and the brake portion sirable in the manufacture of such a combination as 2. The motor is provided with an armature severe vibration encountered. bearings 6 and 7 An object of this invention is to provide an type, within the motor stator member. The

Another object of this invention is to provide shoes 9, and field coils ill, the pole shoes being an improved motor and brake mechanism having 130 secured to the yoke by any suitable means,

the major components molded together to form such as screws ii. The stator assembly is tightly a unitary structure. fitted within a cylindrical enclosing shell l2.

A further object of this invention is to provide The commutator 5 is contacted by a plurality an improved motor and brake mechanism wherein of brushes l3 positioned in brush holder tubes molded insulating material.

Further objects and advantages of this invenextremities to receive brush caps. l6, which may tion will become apparent and the invention will be slotted to a screw driver, as shown at IT.

scription referring to the accompanying draw- I 9 of conductive material which threadingly ings, and the features of novelty which character-1 engages the brush holder tubes, and an outer ize this invention will be pointed out with parsection 20 of insulating material. The brushes ticuiarity in the claims annexed to and forming are biased against the commutator by springs a part of this specification. l8 seated in grooves 2| in the brush holder tubes.

A feature of this invention is the provision The brake mechanism includes a brake coil leads are all bound together and encased in in A non-magnetic retainer washer 26 secures the venting damage due to vibration. stacking. An annular brake armature member In the drawing, Fig. 1, is a side elevational 21 surrounds shaftland is adapted to be actuated view, partly in section, illustrating the improved by the brake coil 24. Brake disk 28 is secured motor and brake mechanism construction of this to the shaft 4 by means of a slip fit spline and invention; Fig. 2 is a view in perspective of the rotates therewith. The outer periphery of the leads prior to assembly and molding; Fig. 3 is assembly is also fitted tightly within the cylinthe other two brush holder tubes and terminals, means. such as rivets 30. The shell is closed and the field coil leads, prior to assembly and at the brake end by an end shield 3| which molding; Fig. 4 is a cross sectional view of the supports the bearing 6 in a bearing recess 32. mechanism of Fig. 1 taken along the line 4-4; 5 The bearing 6 is given the necessary axial bias and washer combination including a plurality of shim washers 33 and spring Washers 34. An annular stationary brake plate 35 is secured to the end shield 3| by suitable means, such as screws 36 and is adjusted for the desired brake action by the use of shim washers 3i. Felt washer 38 is mounted in a groove in the inner periphery of the stationary brake plate 36 and serves to absorb or prevent any oil or grease that may escape from the bearing ii from coming in contact with the brake lining 29 thus greatly reducing the coemcient of friction.

The stator coils Iii are suitably insulated with insulating material 39 and their leads Mi are secured, as by brazing, to the brush holder tubes i4 and terminals 4|. The leads 42 of the brake coil 24 are brought through holes 43 in the face of the brake coil housing member 22 and are also secured, as by brazing, to the brush holder tubes I and terminal 44. The terminals 4| and 44 serve to connect the external leads of the mechanism, as shown schematically in Fig. 8.

In their assembled relation, the stator and brake members are spaced apart and the brush holder tubes i4 and i5 and terminals 4| and 44 interposed therebetween. The brake coil housing member 22, brush holder tubes and terminals, and the stator I are bound together in a fixed relationship by a solid mass of a molded insulating material 45 which encases the stator coils Hi and the stator and brake coil leads 40 and 42, filling the voids in the shell l2 from the central bore of the pole shoes 9 outward. Recessed openings 46 are provided in the molded material 45 between the stator and brake 2 to receive brush caps l6, thus permitting the mounting of the brush caps so that their exterior surface does not project beyond the outer surface of the mechanism. The outer edges of the terminals 4| and 44 are flush with the outer surface of the mechanism, as shown at 4'! in Fig. 1 and in Fig. 5. The shell 12 is provided with four openings 48 and a single opening 49 for the brush holder caps l6 and terminals 4| and 44 respectively. Screws 5|) in the shell I2 and molded material 65 are provided to produce threaded holes in the exterior of the completed mechanism for mounting purposes.

The cavity formed by the shell I2 is closed at the motor end by end shield 5| in which is seated the bearing 1. The bearing is held in position by a bearing retainer member 52 which is secured to the end shield 5| by any suitable means, such as screws 53. A shaft seal 54 is also seated within the end shield 5i and is positioned between the bearing 1 and the armature 3. Power is adapted to be taken from the shaft 5 by suitable means, such as gear 55 which is held in position on the end of the shaft by any suitable means, such as nut 56 and cotter pin 51.

Referring now to Fig. 4, it will be seen that ridges or barriers 58 are molded between the brush holder tubes l4 and i5. These serve to increase the leakage path between the brush holder tubes and brushes i3, thereby reducing the possibility of arc-over between the brushes.

Referring now to terminals 4| are connected to the two series field windings III, which intumare connected in series with the commutator 5 through brushes I3 and the brake coil 24, which in turn is connected to terminal 44. Thus, rotation of the motor in either direction and actuation of the brake is provided with only three external terminals.

Referring again to Fig. 1, a plurality of holes 59 are provided in the face of the brake coil housby a shim ing member 22 and a plurality of mating holes 60 are formed in the molded material 55. A plurality of through bolts 6| are positioned in these holes and serve to secure the end shields 3| and 5| and, in addition, serve as guides for the brake armature member 27. The brake armature is biased against the action of the brake coil 2% by springs 62 which surround the through bolts 66, which also act as guides for the springs.

The method used to make the improved motor and brake mechanism of this invention will now be described. The four stator coils in are wound, formed, insulated with insulation 39, and appropriately interconnected. The stator coil leads 3B are then connected, as by brazing, to the brush holder tubes l4 and the terminals 4|. The pole shoes 9 are then inserted through the field coils Ill and securely anchored to the yoke member 8 by means of screws ii.

The brake coil housing member 22 is next turned from bar stock and the cavity 23 lined with insulation 25. The prewound brake coil 26 is then inserted in the cavity and the non-magnetic retainer Washer 26 inserted and anchored to permanently hold the coil in place. The brake coil leads 42 are brought out through openings 43 in the brake coil housing member and are attached, as by brazing, to the brush holder tubes i5 and terminal Hi. The assembled brake coil housing and coil are then pressed into the shell H and secured by rivets 3|. The assembled stator yoke and coils are next pressed into the shell i2, the coils having been previously insulated with insulation 39. This insulation is applied to prevent damage to the coils in case the molding pressure distorts them or moves them againstthe shell [2 or yoke 8.

The stator, brake, brush holders and terminals are now ready for molding. Referring now to Figs. 6 and '7, there is shown a portion of a mold suitable for performing the molding operation, having anouter shoe portion 63 and an inner removable retainer pot or cavity portion tl. A bottom plug 65 closes the base of the cavity and an upper plug member 56 is positioned at the top of the cavity. A loading chamber member 61 is arranged over the upper plug member and a load ing cavity 68 extends through both members into the cavity portion fie.

In preparing for the molding operation, the assembly described above comprising, the brake coil housing member 22 with its associated insulated brake coil 25, the brush holder tubes i i and i5, the terminals 4| and ed, the leads fill and t3, the yoke 8, the pole shoes 9, and the insulated field coils Hi, all assembled as described above in shell l2, is positioned in the cavity portion 64 of the mold with the brake coil housing member 22 resting on the bottom plug 65. It will be noted that the bottom plug defines with the side wall of the cavity portion 6% a recess 69 in which the brake and extremity of the shell i2 is seated.

Fig. 8, it will be seen that the I Brush holder tube bushings iii are then inserted in the threaded side openings ii in the cavity portion 64. These bushings are provided with an internal. threaded portion 12 and another internal threaded portion 13 which is threaded in the opposite direction, the threaded portion 13 mating with the threaded extremities of brush holder tubes l4 and I5 and the threaded portion 12 being utilized to remove the bushing after molding. The bushings are then threaded onto the brush holder tubes and side pins 14 inserted. Terminal holding plug 15 is then inserted in threaded side opening 15 of the cavity portion M) and 42. As can be The terminal holding plug is provided with three countersunk through holes 11 into which are fitted the tip portions ll 01' terminals and 44. The terminals are provided with internal threaded portions 19 and are secured to the holding plug 15 by means of screws Bil seated in through holes 11.

A center plug member center of the mold.

ing provided for this purpose. This firmly fixes the terminal holding plug 15 and the terminals M and 44 in place for molding.

The cavity portion 64 with the assembled mechanism components positioned and firmly aillxed therein, is vthen inserted in the outer mold shoe portion 63. The upper plug 66 is then positioned over the cavity portion 64. This upper plug member is provided with a plurality of pins 92 secured thereto which provide the through holes B l in the molded structure for through bolts 5!. The loading chamber 6'! is next positioned over the upper plug 66.

The next step is the actual molding operat on. A molding compound is introduced into the mold cavity 64 by any of the several means now well known in the art. Thus, the compound may be introduced directly into the mold cavity and the and injected into the cavity by transfer molding techniques. In the case of the latter technique, the total assembly including the assembled components is subjected to heat and pressure to effect conVerion of the compound to the infusible and insoluble state. In any event, the molding compound is forced under pressure into the cavity portion 64 to fill the voids inside the shell l2 and encasing the coils i0, pole shoes 9, brush holder tubes l4 and I5, terminals 4| and 44, and leads seen, the brake coil housing member 22 serves as the end of the mold while the shell I! constitutes a substantial portion of t e cylindrical surface of the mold.

While either a thermal-plastic or thermal-settingmolding compound may be used, it has been found that a satisfactory compound is one having thermal-setting qualities, for instance, a compound having 41.5% hard rubber of high sulphur content, 12.5% cumarone-indine resin, 27% long fibre asbestos, and 18% phenol-formaldehyde resin. This material molds at a low pressure on the order of 800 lbs. per square inch and cures at a temperature on the order of 32 F. for minutes.

The molding operation having been completed. the loading chamber 81 and upper plug 66 are removed and the cavity portion 84 removed, the A hole plugs I! and 88, bushings I0, screws 80, 16 are then removed.

side pins 14, brush holder and terminal The mechanism is now ready for complete assembly bearings, and end shields.

It can now be readily seen that the forgoing method provides an improved motor and brake mechanism characterized by its light and compact construction and freedom from damage due to vibration.

While there has been illustrated and described a specific embodiment of the invention, further embodiments will occur to those skilled in the art spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A motor and brake mechanism comprising, a stator member for said motor including a core with coils, a plurality of brush holder member:- for said motor, a housing member for said brake,

' and insulating material binding all of said members together in said core and is provided.

2. A motor and brake mechanism comprising. a stator member for said motor including a core with coils, a plurality of brush holder members for said motor, a plurality oi terminal members for connecting the external leads to said mechanism, a housing member for said brake, and insulating a fixed relationship and encasing coils whereby a unitary structure material binding all of said members together in a relationship and encasing said core and coils whereby a unitary structure is provided.

3. A motor and brake mechanism comprising, a stator member for said motor including a core with coils, a plurality of brush holder members for said motor, a housing member for said brake having a brake actuating coil associated therewith, electrical conductors for connecting said brush holder members to said stator and brake co ls. and a mass of molded insulating material binding all of said members together in a fixed unitary structure is provided.

4. A motor and brake mechanism comprising, a stator member for said motor including a core with coils, a plurality of brush holder members for said motor, a plurality of terminal members for connecting the external leads to said mechan sm, a housing member for said brake having a brake actuating coil associated therewith, electrical conductors for connecting said brush holder members and said terminal members to said stator and brake coils, and a mass 01' molded insulating material binding all of said members t0- gether in a fixed relationship and encasing said core and stator coils and said electrical conductors whereby a unitary structure is provided.

5. A motor and brake mechanism comprising, a shell, a stator member for said motor including 7 a core with coils and adapted to fit within said shell, a plurality of brush holder members for said motor, a plurality of terminal members for connecting the external leads to said mechanism,

a housing member for said brake having a brake actuating coil associated therewith, electrical conductors for connecting said brush holder members and said terminal members to said stator and brake coils, and a mass of molded insulating material binding all of said members together in a fixed relationship and filling the voids in said shell whereby a unitary structure is provided, said core and stator coils and said electrical conductors being encased in said insulating material.

6. A motor and brake mechanism comprising, a stator member for said motor including a core with coils, a housing member for said brake spaced from said stator member and having a brake actuating coil associated therewith, a plurality of brush holder members for said motor positioned between said stator and brake housing members, electrical conductors for connecting said brush holder members to said stator and brake coils, and a mass of molded insulating material binding all of said members together in a fixed relationship and encasing said core and stator coils and said electrical conductors whereby a unitary structure is provided.

7. A motor and brake mechanismcomprislng, a stator member for said motor including a core with coils, a housing member for said brake spaced from said stator member and having a brake actuating coil associated therewith, a plurality of brush holder members for said motor posltionedbetween said stator and brake housing members, a plurality of terminal members for connecting the external leads to said mechanism positioned between said stator and brake housing members, electrical conductors for connecting said brush holder members and said terminal members to said stator and brake coils, and a mass of molded insulating material binding all of said members together in a fixed relationship and encasing said core and trical conductors whereby a unitary structure is provided.

8. A motor and brake mechanism comprising, a shell, a stator member for said motor including a yoke with a plurality of field poles extending inwardly defining a central bore and adapted to fit within said shell, a housing member for said brake spaced from said stator member and having a brake actuating coil associated therewith, a plurality of brush holder members for said motor positioned between said stator and brake housing members, a plurality of terminal members for connecting the external leads to said mechanism positioned between said stator and brake housing members, electrical conductors for connecting said brush holder members and said terminal members to said stator and brake coils, a mass of molded insulating material filling the space within said shell from the bore of said poles outwardly and binding all of said members together in a fixed relationship whereby a unitary structure is provided, and field coils positioned on said poles, said field coils and said electrical conductors being encased in said insulating material.

9. A motor and brake mechanism comprising, a stator niember for said motor including a core with coils, a plurality of brush holder members for said motor adapted to receive contact brushes, a brake housing member for said brake having a brake actuating coil associated therewith,

stator coils and said eleca aeeaoiv electrical conductors for connecting said brush holder members to said stator and brake coils, and a mass of molded insulating material binding all of said members together in a fixed relationship and encasing said core and stator coils and said electrical conductors whereby a unitary structure is provided, said molded insulating material forming barriers between said brush holder members whereby the creepage distance between said brushes is increased preventing arc-over therebetween.

10. A motor and brake mechanism comprising, a shell, a stator member for said motor including a yoke with a plurality of field poles extending inwardly defining a central bore and adapted to fit within said shell, a housing member for said brake spaced from said stator member and having a brake actuating coil associated therewith, a plurality of brush holder members for said motor positioned between said stator and brake housing members and adapted to receive contact brushes, a plurality of terminal members for connecting the external leads to said mechanism positioned between said stator and brake housing members, electrical conductors for connecting said brush holder members and said terminal members to said stator and brake coils, a mass of molded insulating material filling the space within said shell from the bore of said poles outwardly and binding all of said members together in a fixed relationship whereby a unitary structure is provided, and field coils positioned on said poles, said field coils and said electrical conductors being encased in said insulating material, said molded insulating material forming barriers between said brush holder members whereby the creepage distance between said brushes is increased preventing arc-overtherebetween.

11. A motor and brake mechanism comprising, a stator member for said motor including a core with coils, a plurality of brush holder members for said motor, a plurality of terminal members for connecting the external leads to said mechanism, a housing member for said brake having a cavity formed therein, a brake actuating coil positioned in said cavity, electrical conductors connecting said brush holder and terminal members to said stator and brake coils, a brake armature adapted to be actuated by said brake coil, a plurality of fastening means extending through said stator and brake housing members, each of said means having one end adapted to secure an end shield to said stator member and having the other end adapted to serve as a guide for said brake armature, and a mass of molded insulating material binding all of said members together in a fixed relationship and encasing said core and stator coils and said electrical conductors whereby a unitary structure is provided.

12. A motor and brake mechanism comprising, a shell, a stator member for said motor including a yoke with a plurality of field poles extending inwardly defining a central bore and adapted to fit within said shell, 3, housing member for said brake spaced from said stator member and having a cavity formed therein, a brake actuating coil positioned in said cavity, a plurality of brush holder members for said motor positioned between said stator and brake housing members, a plurality of terminal members for connecting the external leads to said mechanism positioned between said stator and brake housing'members, electrical conductors connecting said brush holder members and said terminal members to said stator and brake coils, a brake armature electrical conductors being encased in said plurality of fastemng means extending through insulating material.

GLENN D. WILLITS. REFERENCES CITED Thefollowi ng references are of record in the ill of thi atent: filling the space within said shell from the bore 0 s p UNITED STATES PATENTS Name Date Apple May 17, 1932 Apple Aug. 30, 1932 

